Thursday, March 27, 2008

Normally, Lean and Six Sigma tools provide additional benefits very quickly. For example, it is common that the constraint resource could benefit from set-up reduction. Focusing Lean tools—which cost little to implement—results in additional capacity where it is needed and that has an immediate bottom-line result.

Due-date performance improves because of the reduction in lead-time, the increased capacity, the predictability of the time to process an order has improved, and jobs are prioritized according to due date.

The “Drum” is the schedule for the constraint resource. It sets the pace for the entire operation. In Goldratt's Theory of Constraints, we assume there is one system constraint that is limiting the throughput of the entire business. The drum is the only resource that needs to be scheduled. All other operations have relative excess capacity, meaning that orders can flow through the plant until reaching the constraint resource, and after it.

The “Buffer” is what protects the constraint from going idle from lack of material to process. The buffer needs to be large enough to prevent starvation on the constraint resource. It is really a time buffer, not physical materials, but we’ll explain that at another time.

The “Rope” is the mechanism for release of new material into the operations.

There are conventional cost accounting assumptions that may block you from implementing Drum-Buffer-Rope. Next time, we’ll address those issues, and describe how TOC’s Throughput Accounting concepts will free you to take the needed actions.

______________________________________________________________________ About About the co-authors:

Brad Stillahn is a business owner that has successfully implemented TOC methods in his own business and is now helping other business owners do the same. His consulting company, TOC Professionals engages in long-term relationships with companies implementing TOC. His business and personal partner is Dr. Lisa Lang. Brad can be reached at Brad@ScienceofBusiness.com or 303-886-9939.